Choke and dash adjustment for carburetors



Oct. 22, 1935. R. F. BRACKE CHOKE AND DASH ADJUSTMENT FOR cmauma'fons Original Filed July 5, 1927.

Patented Oct. 1935 PATENT OFFICE CIiOKE AND DASH-ADJUSTMENT FOR CARBURETORS Robert F. Bracke, Chicago, 111., assignor, by mesne assignments, to Lynn A. Williams, n,- 111., and Cliiiord C. Bradbury, Glencoe, 111.,

successor trustees Application July 5, 1927, Serial No. 203,295 g Renewed February 8, 1934 7 Claims. (or. 137-139) My invention relates to improvements in choke and dash adjustments for carburetors. It will be explained as embodied in the ordinary type 01' carburetor for the internal combustion engine of a motor vehicle having an instrument board upon which the manually operated dash control is mounted. The inventioncontemplates the use of an automatically operableair inlet or throttle valve of the butterfly type having one 10 lobe larger than the other and which opens against a spring by atmospheric pressure due to the resultant difierential of air pressure on the two lobes. In the present type of automatic air valve having a large and a small lobe, the axis 15 of the valve is either to one side of the diametrical center of the bore of the air inlet thus necessitating the building up of flats on the side walls of the bore adjacent the valve axis or in an imperfect and leaky fit between valve and'bore, or

go the. axis 'the valve coincides with the diametrical center of the bore and one outer wall of the bore is built out toward the axis to compensate for the decreased lobe area. This latter construction greatly reduces the capacity of the air 5 inlet while the former construction involves mechanical difilculties resulting in high manufacturing cost or a valve which performs unsatisfactorily because of leakage: 4

One of the objects of the invention is to pro- 0 vide an improved combined choke and dash adjustment for carburetors.

Another object is to provide a choke and dash adjustment including an automatically operable air inlet valve of the character described which 35 may be fitted within the air inlet bore of the or-,

dinary type of carburetor without altering the walls of the bore with which the valve engages.-

A further object is to provide an improved choke and dash adjustment including an auto- 40 matically operable air inlet valve of the character described wherein a complete seal between the valve and inlet bore is efiected.

Another object is'to provide in an improved 45 choke and dash adjustment for carburetors, an

butterfly type having one lobe of greater area than the other which is so fashioned as to completely close the cylindrical bore of the carburetor air inlet when rotated upon an axis coinciding with the diametrical center of the bore.

.Another object is to provide a choke and dash adjustment for carburetors which may be controlled so as to perform any one of its three 55 principal functions by the movement of a conautomatically operable air inlet valve of the trol member'mounted upon the instnunent board of the vehicle. 1

' Another object is to provide an improved choke and dash adjustment for carburetors which when desired performs the function of an auxiliary air 3 valve to enrich the mixture in the carburetor by restricting the air inlet of the carburetor to a degree determinable by induction passage vacuum.

A further object is to provide an improved 0 choke and dash adjustment in which the valve may be closedto perform the iunctionoi the ordinary choke by completely or nearly closing the air intake to the carburetor.

A further object is to provide a combined choke and dash adjustment for carburetors which may be set so as to become entirely ineffective as either an auxiliary air valveor a choke at which time air may be drawn into the carburetor through the air inlet without restrlcq tion of any sort.

A further object is to provide an improved choke and dash adjustment for carburetors which is-adaptable toall types of carburetors in which air is drawn thereinto through a principal economically.

Other objects and advantages will hereinafter appear.

' An embodiment of the invention is illustrated in the-accompanying drawing wherein:

Figure 1 is a side' elevation partially in section of a carburetor embodying the choke and dash adjustment and in which a sectional view of the dash control member is shown;

Figure 2 is'a view partly in section along the 40 .line 2-2 of Figure 1;

Figure 3 is a side elevation of a part ofthe mechanism illustrated in Figure 1 as set for nor mal running position; I a

. Figure 4 is a view similar to Figure 3 showing the adjustment set for choking position. 1

I have illustrated the invention'as applied to. a carburetor for the internal combustion engine of an automobile in which A represents the induction passage, B the principal air inlet, C the so fuel nozzle, D the engine manifold and E the throttle valve for controlling the passage oi. fuel to the intake manifold D, of the engine.

The choke and dash adjustment in general consists of a butterfly air inlet valve V of specialw spring S tending to close the valve and a manually operated dash control M mounted upon the instrument board N of the vehicle.

. valve V is carried by a shaft 5 extending The valve consists of two lobes 6 and I. The lobe 6 when the valve is closed, extends at an angle of 45 toward the carburetor body from a plane through the axis of shaft 5 disposed transverse to the air inlet B. The lobe I extends slightly away from the aforesaid plane on the opposite side. Thus the lobe 5 has a relatively greater surface than the lobe l and when unrestrained; suction in the induction passage A will cause the valve to open upon the greater application of atmospheric pressure upon lobe 6.

With reference to Figure 1 it will be noted that lobe 6 of the valve V when closed extends toward the direction of the movement of the valve to its open position while lobe-1 lies in a plane subv st'antially transverse to the bore of the air inlet B. This peculiar arrangement of the lobes and I affords greater surface area in lobe 5 and permits free movement of that lobe to a position parallel with the axis of the bore (Fig. 3) upon its pivotal axis or shaft 5.

In order to assure maximum passage of air "through the air inlet B when the valve is open as shown in Figure 3, the air inlet B is provided with a diametrically enlarged portion 8 immediately beyond thef shaft 5 of the valve so that the lobe 1 extends into the enlarged portion 8 of the air inlet when the valve is open.

The shaft 5 has at its outer end a pair of stop arms in and il secured to the shaft by a screw l2 extending through the threaded bore of a body l3 commonto the arms. Thus the arms may be adjusted with respect to the shaft 5. A stopmember I! extending outwardly from the enlarged portion 8 of the air inlet serves tolimit movement of the valve V in aclockwise direction (see Figure 3) so that movement in that direction will bring the valve to a stop in full open position as required during normal operation of the engine for which the carburetor is used.

The shaft 5 has rotatably mounted thereon between the body l3 and the adjacent shaft bearing I 6, an arm I! extending radially beyond the ends of the stop arms l0 and II. The spring S is secured at one end l8 to the: arm I1 and at its opposite end to the stop arm II as shown at l9.

Thus the spring yieldingly urges the valve V to' its closed position as shown in Figure 1.

The arm l1, has alaterally extending abutment 22 against which the inner faces 23 of the stop arms Ill and II may move to limit rotational movement of the valve depending upon the posi tion of arm [1.

The outer end of the arm II has a connecting member 24 to which one end of a flexible wire 25 is secured.

The wire 25 is conducted upwardly through a flexible tube 26 to the instrument board N of the motor vehicle and the upper end 26' of the wire 25 is secured to a reciprocable frictionally mounted plunger 21 forming a part of the manual control member M. This plunger 21 has a hand grip 28 at its outer end by means of which the plunger may be moved to'cause proportional movement of the arm li.

In operation, when starting an engine having a carburetor equipped with my -improved choke and dash adjustment, the plunger 21 is drawn outwardly beyond the position shown in Figametrically across the bore of the air inlet 3..

' construction mounted within the air inlet B, a

ure 1, thus causing the arm I! to assume the position shown in Figure 4, the abutment 22 engaging with the face 23 or the stop arm 'to positively maintain valve V in the position shown therein so that the valve closes the air inlet B. 5 At this time lobes 6 and I of the valve V will contact with the bore ofginlet- B throughout their entire peripheral edges. In this position the carburetor air inlet is choked so that the raw fuel is drawn into the manifold D as is necessary for starting the engine when cold.

Afterthe engine is started theplunger2i is moved to the position shown in Figure 1 at which time the arm I! permits rotation of the shaft'5 greater than that shown in Figure 1 at which time the abutment-22 on the arm I i serves as a positive stop against complete closure of the I valve V by spring S at such times as the induc-' tion passage vacuum may drop sufllciently to 305 permit the -spring to so function.

During normal conditions the plunger 21 is moved inwardly from the position shown in Figure 1 so as to cause abutment 22 of the arm IT to force stop arm Ill against the stop it thus positively loclnng the valve in wide-open position as shown in Figure 3.

I claim:

1. An air regulating valve of the character described pivotally mounted diametrically of the 40.: axis of the intake passage of a carburetor by a shaft, lobes for said valve, one of which is of greater area than the other and extending at an oblique angle relative the air passage to con- I form to the internal diameter of said passage 5: when closed, a member fixed to the shaft having diverging arms, and a stop for engagement by-one of said arms to limit the movement of the valve to open position, an arm pivotally supported on said shaft and adapted to engage the 1 spring.

2. An air regulating valve of the class described mounted in the air intake passage of a carburetor, a shaft, lobes mounted in obtuse relation on said shaft, one lobe having a substantially greater area than the other, stops mounted on said shaft, means manually operable cooperating withsaid stops, to control said valve and to hold it in unyielding position at points when said valve is completely opened or closed, resilient means cooperating with said manually operable means and said shaft, to urge said valve normally to closed position and yielding to a differential of pressure on the two lobes.

3. An air regulating valve of the ,character is described mounted in the air intake passage of a carburetor, comprising a shaft diametrically mounted in said passage, lobes mounted on said shaft, one of the lobes having a substantially greater area than the other, said lobes being in an angular relation of about 150 with each other, integral arms mounted on said shaft exterior of said passage, means cooperating with said arms adapted to be manually operated to actuate said valve to open and closed positions, resilient means operating between said arms and manually operable means, to urge said valve normally to closed position, and yieldable to-pneumatic force on said valve lobes.

4. An air regulating valve of the class described mounted in the air intake passage of a carburetor, a shaft, lobes mounted in obtuse relation on said shaft, one lobe having a substantially greater area than the other, stops mounted on said shaft, means, manually operable, cooperating with said stops to control said valve and to unyieldingly hold it in completely opened or closed position, means urging said valve normally to closed position and yielding to a difpositions, the arm and stop member being constructed and arranged with a lost motion connection therebetweenwhereby the stop member may set the arm in fully closed and in full opened positions of the valve, and a resilient spring in terposed between the arm and stop member urg ing the valve to its closed position.

6. In a carburetor for an internal combustion engine, an intake passage therefor, a shaft journaled transverselytherein, a butterfly valve on the'shaft having lobes of unequal area whereby the v-alve tends to open upon increased suction in the passage posteriorly of the valve, a.

double arm on the shaft externally of the passage, 5

a stop lever journaled on the arm, a manual control for holding the arm in a plurality of adjusted angular positions, the arms of the double arm cooperating with the stop arm to form a lost motion connection therebetween, and a resilient spring interposed between the double arm and the stop arm and arranged to urge the valve to?- ward its closed position, the stop arm in one position holding the valve fully closed and in another position holding it fully opened and in intermediate positions positioning the valve through the resilience of the spring.

'I. In a carburetor for an internal combustion engine, an intake passage therefor, a butterfly choke valve rotatably mounted in the passage and having lobes of unequal area constructed and arranged to tend to open the valve upon increased suction in the passage posteriorly of the valve, an operating arm on the valve, a movable manually controlled stop member having a plurality of adjusted positions, the arm and stop member being constructed and arranged with a lost motion connection therebetween, a resilientspring interposed between the arm and stop member urging the valve to closed position, the stop memher, when in one position, engaging the arm to hold the valve fully closed, and in another position engaging the arm to hold the valve fully open, and in intermediate positions tending to position the valve through the resilient spring whereby the valve in at least a portion of the range of its path, and including closed position, may be moved relative to the stop member by changes in the suction in the passage.

ROBERT F. BRACKE. 

